There are many known dispenser devices for dispensing viscous material. Such devices have been employed in a variety of applications for discharging many different types of viscous materials. A common application for dispensers of this kind is in the field of cosmetic applicators. Typical cosmetic applicators are pen-like in design and dispense a cosmetic fluid onto an integrally disposed applicator when actuated by the user.
Pen-like fluid dispensing devices for manual user operation, especially those devices used for dispensing cosmetic fluids, must be capable of being fabricated inexpensively from readily available materials. In addition to the importance of minimizing manufacturing costs, it is equally important that such devices be fabricated to close tolerances in order to ensure proper fit and cooperative inter-engagement between both fixed and relatively movable parts, and to provide for reliable operation of the dispenser throughout its intended useful life which is usually until the initial supply of stored fluid is exhausted. In the case of cosmetic fluid dispensers, assuring continued operative reliability is much more difficult. This is because cosmetic fluids such as nail enamels, are relatively caustic to many common construction materials and quickly thicken and harden in the absence of adequate fluid tight seals, makes continued operative reliability much more difficult.
Typical known and commercially available dispenser devices commonly employ relatively complex mechanical designs which use large numbers of mutually engaging parts that must all cooperatively interact in order for the device to operate. Dispenser devices of this type are usually difficult and expensive to manufacture and often exhibit high failure rates as the devices approach the end or latter portion of their intended, useful lives. Moreover, many of these devices are difficult to operate.
Accordingly, there is a need for a dispenser device for dispensing metered doses of viscous material with enhanced reliability and ease of operation.